A significant barrier to shifting advertisement budgets to the online channel is the inability to measure the effectiveness and/or impact of an online advertisement campaign on offline sales, e.g., brick and mortar sales. Measurement, or metrics, that have been used for online campaigns are typically based on click through rate (CTR), surveys or offline impact analysis based on a panel of users. Missing in the measurement of online advertisement effectiveness is data from offline sales. Since a significant percentage, e.g., approximately 95%, of the total commerce in the United States, is derived from offline sales, it would be beneficial to be able to make use of data from offline sales to determine the effectiveness of online advertising, and to measure causality between exposure to an online display ad and an offline sales event(s).